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From: "Namjae Jeon" <namjae.jeon@samsung.com>
To: "'Tetsuhiro Kohada'" <kohada.t2@gmail.com>
Cc: <kohada.tetsuhiro@dc.mitsubishielectric.co.jp>,
	<mori.takahiro@ab.mitsubishielectric.co.jp>,
	<motai.hirotaka@aj.mitsubishielectric.co.jp>,
	"'Sungjong Seo'" <sj1557.seo@samsung.com>,
	<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v3] exfat: integrates dir-entry getting and validation
Date: Wed, 26 Aug 2020 13:19:09 +0900	[thread overview]
Message-ID: <002e01d67b60$0b7d82a0$227887e0$@samsung.com> (raw)
In-Reply-To: <d1df9cca-3020-9e1e-0f3d-9db6752a22b6@gmail.com>

> On 2020/08/26 10:03, Namjae Jeon wrote:
> >> Second: Range validation and type validation should not be separated.
> >> When I started making this patch, I intended to add only range validation.
> >> However, after the caller gets the ep, the type validation follows.
> >> Get ep, null check of ep (= range verification), type verification is a series of procedures.
> >> There would be no reason to keep them independent anymore.
> >> Range and type validation is enforced when the caller uses ep.
> > You can add a validate flags as argument of exfat_get_dentry_set(), e.g. none, basic and strict.
> > none : only range validation.
> > basic : range + type validation.
> > strict : range + type + checksum and name length, etc.
> 
> Currently, various types of verification will not be needed.
> Let's add it when we need it.
> >
> >>> -	/* validiate cached dentries */
> >>> -	for (i = 1; i < num_entries; i++) {
> >>> -		ep = exfat_get_dentry_cached(es, i);
> >>> -		if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
> >>> +	ep = exfat_get_dentry_cached(es, ENTRY_STREAM);
> >>> +	if (!ep || ep->type != EXFAT_STREAM)
> >>> +		goto free_es;
> >>> +	es->de[ENTRY_STREAM] = ep;
> >>
> >> The value contained in stream-ext dir-entry should not be used before validating the EntrySet
> checksum.
> >> So I would insert EntrySet checksum validation here.
> >> In that case, the checksum verification loop would be followed by the
> >> TYPE_NAME verification loop, can you acceptable?
> > Yes. That would be great.
> 
> OK.
> I'll add TYPE_NAME verification after checksum verification, in next patch.
> However, I think it is enough to validate TYPE_NAME when extracting name.
> Could you please tell me why you think you need TYPE_NAME validation here?
I've told you on previous mail. This function should return validated dentry set after checking
file->stream->name in sequence.
> 
> 
> BR
> ---
> Tetsuhiro Kohada <kohada.t2@gmail.com>
> >


  reply	other threads:[~2020-08-26  4:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200806010249epcas1p18fd6e3febad305975b43e1b55b56bcae@epcas1p1.samsung.com>
2020-08-06  1:02 ` Tetsuhiro Kohada
2020-08-08 16:35   ` Sungjong Seo
2020-08-10  6:10   ` Namjae Jeon
2020-08-12 13:25     ` Tetsuhiro Kohada
2020-08-21  6:53       ` Namjae Jeon
2020-08-25  8:21         ` Tetsuhiro Kohada
2020-08-26  1:03           ` Namjae Jeon
2020-08-26  2:56             ` Tetsuhiro Kohada
2020-08-26  4:19               ` Namjae Jeon [this message]
2020-08-26  6:07                 ` Tetsuhiro Kohada
2020-08-26  7:32                   ` Namjae Jeon
2020-08-27  9:59                     ` Tetsuhiro Kohada

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